20500217 has 2 divisors, whose sum is σ = 20500218. Its totient is φ = 20500216.

The previous prime is 20500189. The next prime is 20500219. The reversal of 20500217 is 71200502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10394176 + 10106041 = 3224^2 + 3179^2 .

It is a cyclic number.

It is not a de Polignac number, because 20500217 - 2¹² = 20496121 is a prime.

Together with 20500219, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 20500195 and 20500204.

It is not a weakly prime, because it can be changed into another prime (20500219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10250108 + 10250109.

It is an arithmetic number, because the mean of its divisors is an integer number (10250109).

Almost surely, 2^20500217 is an apocalyptic number.

It is an amenable number.

20500217 is a deficient number, since it is larger than the sum of its proper divisors (1).

20500217 is an equidigital number, since it uses as much as digits as its factorization.

20500217 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 140, while the sum is 17.

The square root of 20500217 is about 4527.7165326465. The cubic root of 20500217 is about 273.6861494224.

Adding to 20500217 its reverse (71200502), we get a palindrome (91700719).

The spelling of 20500217 in words is "twenty million, five hundred thousand, two hundred seventeen".